I love this question.  I can see the thread metaphor working.  The rubber band not so much for me.  I have broken too many of them by stretching them too far.  And yes they do break with a suddeness and a snap.  Was it Blondie who sang "Love is a battlefield"?  While I can relate to that idea, I don't like it.  For me, love is a symphony.  With many different instruments (experiences?) involved.  Each having a 'time in the sun', so to speak.  With the dynamics changing, soothing in parts, loud and crashing in other parts.  But all of the parts telling a unique story as a whole.  As I said,I love this question. 

You touch us all with this beautiful question.  Love is something we will never totally understand as we do move in and out of love.  Even in the strongest relationships time will heal wounds and rough them up.  It is a learning process that continues not just with our lives but from our past and to our future.  We are evolving we pass on this invisible communication threads that are not possible to explain.  It is the unknowing faith of love that goes from one to another.  Just look at our newest form of communication the computer and texting.  As I write this we feel something in side ourselves.  Is it me in you or is it just our invisiblle souls connecting as we have always done before we were sent down to earth.  These threads of life are so meaningful and such a blessing.